Looking for a matlab script that extracts data from a plot figure ( here 2D contours from Covariance matrix or Markov chains) and reproduce the original figure

조회 수: 5 (최근 30일)
I am looking for a script which is able for example to extract data from a 2D contours plot like below :
I tried to apply the method in Matlab with the script below from this post :
%// Import the data:
imdata = importdata('Omega_L_Omega_m.png');
Gray = rgb2gray(imdata.cdata);
colorLim = [-1 1]; %// this should be set manually
%// Get the area of the data:
f = figure('Position',get(0,'ScreenSize'));
%// Get the area of the data:
title('Click with the cross on the most top left area of the *data*')
da_tp_lft = round(getPosition(impoint));
title('Click with the cross on the most bottom right area of the *data*')
da_btm_rgt = round(getPosition(impoint));
dat_area = double(Gray(da_tp_lft(2):da_btm_rgt(2),da_tp_lft(1):da_btm_rgt(1)));
%// Get the area of the colorbar:
title('Click with the cross within the upper most color of the *colorbar*')
ca_tp_lft = round(getPosition(impoint));
title('Click with the cross within the bottom most color of the *colorbar*')
ca_btm_rgt = round(getPosition(impoint));
cmap_area = double(Gray(ca_tp_lft(2):ca_btm_rgt(2),ca_tp_lft(1):ca_btm_rgt(1)));
%// Convert the colormap to data:
data = dat_area./max(cmap_area(:)).*range(colorLim)-abs(min(colorLim));
It seems that I get data in "data" array but I don't know how to exploit it to reproduce the original figure from these data.
Could anyone see how to plot with Matlab this kind of plot with the data I have normally extracted (not sure the Matlab. script has generated all the data for green , orange and blue contours, with each confidence level, that is to say, 68%, 95%, 99.7%) ?
Any help is welcome to reproduce this figure with extracted values.
Thanks in advance

채택된 답변

Joseph Cheng
Joseph Cheng 2021년 6월 9일
편집: Joseph Cheng 2021년 6월 9일
your graph is a bit messy with text and lines that denote items. here is a quick example that may push you along. It'll need a lot of work to fill in holes created by text and the dotted boundary lines but here is a start.
clear all;
imdata = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/642495/image.png');
close all;
Gray = rgb2gray(imdata);
yax=sum(conv2(single(Gray),[-1 -1 -1;0 0 0; 1 1 1],'valid'),2);
xax=sum(conv2(single(Gray),[-1 -1 -1;0 0 0; 1 1 1]','valid'),1);
ROIy = find(abs(yax)>1e5);
ROIyinner = find(diff(ROIy)>5);
ROIybounds = ROIy([ROIyinner ROIyinner+1]);
ROIx = find(abs(xax)>1e5);
ROIxinner = find(diff(ROIx)>5);
ROIxbounds = ROIx([ROIxinner ROIxinner+1]);
PLTregion = Gray(ROIybounds(1):ROIybounds(2),ROIxbounds(1):ROIxbounds(2));
[N X]=hist(single(PLTregion(:)),0:255);
PLTitems = find(N>2000)% %limit "color" of interest to items with >1000 pixels
PLTitems = 1×10
1 67 90 101 129 132 144 167 180 194
PLTvalues = X(PLTitems);
PLTvalues(1)=[]; %ignore black?
%test out region 1
for ind = 1:numel(PLTvalues)
temp = zeros(size(PLTregion));
temp(PLTregion==PLTvalues(ind) | (PLTregion<=50 & PLTregion>10))=255;
% figure(100), imagesc(temp)
temp = bwareaopen(temp,1000);
temp = imfill(temp,'holes');
figure(100), subplot(3,3,ind),imagesc(temp)
figure(101), subplot(3,3,ind),imagesc(single(PLTregion).*temp,[0 255])

추가 답변 (1개)

petit 2021년 6월 12일
Thanks for your detailled answer. I realize there is a lot of work to do more to extract these covariance matrices from this image.
Which track do you suggest me to go deeper in this analysis ?
By chance, do you know external tools which could allow to perform easily this extraction ? Maybe similar functionality in the File exchange forum has been done ?
Best regards


Help CenterFile Exchange에서 Contour Plots에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by